1. Field of the Invention
The present invention relates to a method of measuring a receive power of a CDMA mobile communication system, and in particular, to a method of obtaining a total receive power of uplink frames that are not transmitted over a predetermined channel such as a dedicated channel at a base station, and to a CDMA mobile communication system adopting the method.
2. Description of the Related Art
A conventional method of measuring a receive power in a code division multiple access (hereinafter, referred to as “CDMA”) mobile communication system will be described with reference to FIGS. 11 and 12. The conventional method of measuring a receive power is disclosed in, for example, Japanese Patent Application Laid-open No. 2004-215276A and JP 2000-175256 A. FIG. 11 is a block diagram showing a configuration of the conventional CDMA mobile communication system, and FIG. 12 is a timing chart showing an operation of the conventional CDMA mobile communication system. Part “A” of FIG. 12 is indicated in “FIG. 12-(A)”, and such representation is used in the following FIGS.
A base station (hereinafter, referred to as “BS”) 1 transmits downlink frames, BCH(N), BCH(N+1), BCH(N+2), . . . , over a broadcast channel (hereinafter, referred to as “BCH”). Herein, N is a natural number, and BCH(N) represents an Nth frame transmitted over a BCH. Mobile stations (hereinafter, mobile station is referred to as “MS”) 2-1 to 2-3 are placed at positions sufficiently close to one another with respect to the transmission speed of radio waves, so they receive BCH(N), BCH(N+1), BCH(N+2), . . . substantially concurrently.
Among MSs that have received downlink frames BCH (N), BCH(N+1), BCH(N+2), . . . , transmitted over a BCH, MS 2-1 transmits uplink frames (hereinafter, referred to “non-EDCH”), non-EDCH(N), non-EDCH(N+1), non-EDCH(N+2), . . . over one or more channels, but not over an enhanced dedicated channel (hereinafter, referred to as “EDCH” (FIG. 12-(B)). Herein, N is a natural number, and non-EDCH(N) represents an Nth frame transmitted over a non-EDCH. The BS 1 receives the non-EDCH (N), non-EDCH(N+1), non-EDCH(N+2), . . . . The EDCH is, for example, a kind of a dedicated channel for providing a high data rate of an uplink, a standardization of which is being studied in a 3rd generation partnership project (3GPP).
Furthermore, the MS 2-2 that has received BCH(N), BCH(N+1), BCH(N+2), . . . transmits uplink frames, EDCH1(N), EDCH1(N+1), EDCH1(N+2), . . . transmitted over an EDCH (FIG. 12-(C)). Herein, N is a natural number, and EDCH1(N) represents an Nth frame transmitted over an EDCH. A subscript “1” represents a frame transmitted by MS 2-2. BS 1 receives the EDCH1(N), EDCH1(N+1), EDCH1(N+2), . . . .
Similarly, the MS 2-3 that has received BCH(N), BCH(N+1), BCH(N+2), . . . transmits uplink frames, EDCH2(N), EDCH2(N+1), EDCH2(N+2), . . . transmitted over an EDCH (FIG. 12-(D)). Herein, N is a natural number, and EDCH2(N) represents an Nth frame transmitted over an EDCH. A subscript “2” represents a frame transmitted by MS 2-3. BS 1 receives the EDCH2(N), EDCH2(N+1), EDCH2(N+2), . . . .
Then, BS 1 obtains a total of the receive powers of three uplink frames of the non-EDCH, EDCH1, and EDCH2 respectively from MSs 2-1 to 2-3.
At this time, as shown in FIG. 12-(E), the receive power obtained by BS 1 is a total of the receive power of the non-EDCH and the total of the receive powers of the EDCH1 and uplink EDCH2. That is, BS 1 cannot obtain the total of the receive power only of the non-EDCH, which is not transmitted over EDCHs.
As examples of techniques for maintaining communication quality, there are an admission control and a congestion control. Herein, the admission control is a control of limiting making connections over a network so as to keep a quality of service of an existing connection in a case where a network traffic of a radio line reaches a saturation point of the network capacity. Furthermore, the congestion control is a control of decreasing a communication rate mainly of an existing connection of a packet user and changing a channel from a dedicated channel to a common channel so as to keep a quality of the existing connection in a case where the network traffic of a radio line reaches a saturation point of the network capacity.
In the CDMA mobile communication system, in order to perform the admission control and the congestion control of uplink non-EDCHs, it is necessary to use the total receive power of the non-EDCH frames, frames transmitted not over EDCHs that are dedicated channels, from each MSs.
However, as described above, according to the conventional method of measuring a receive power, a total receive power of non-EDCHs cannot be measured. Thus, there arises a problem in that the admission control and the congestion control using the total receive power of non-EDCHs cannot be performed.